Alexandru Petrescu, National Institute for Metals and Radioactive Resources (Romania)Ilie Oancea, National Institute for Metals and Radioactive Resources (Romania)Ovidiu Sorin Mihai, National Institute for Metals and Radioactive Resources (Romania)

Methods for monitoring seepage and detecting internal erosion are essential for the safety evaluation of tailings dams. Internal erosion is one of the major reasons for tailings dam failures and it is difficult to detect it by conventional methods. Therefore, there is a strong need of new or improved non-destructive detection methods. In this research we have used geoelectrical method; the investigation technique was electrical resistivity imaging (ERI). Data were acquired by using some conventional arrays (Wenner-Schlumberger, dipole-dipole and Wenner). These arrays were placed such as to permit us to obtain a 3D image of resistivity distribution inside the tailings dam. The apparent resistivity sections were inverted by using Res2DInv software. In this paper we present the results obtained by using this methodology in a case study: the tailings pond dam of Uranium Milling Plant Feldioara, Brasov County. Geoelectrical investigations distinguish a series of resistivity anomalies; the interpretation of these anomalies indicates the presence of some possible instability areas inside the dam.